Masking material

ABSTRACT

The object of the present invention is to manufacture a masking member having a complex shape and being highly accurate. To attain said object, the present invention provides a masking member made of a modified polypropylene in which 5 to 30% by weight of polyethylene and/or ethylene-propylene copolymer is mixed in with polypropylene. In a case where polyethylene and/or ethylene-propylene copolymer is mixed in with polypropylene, the elongation of said polypropylene improves, also improving its moldability.

FIELD OF THE INVENTION

The present invention relates to a masking member used to protect aspecific part of an article not to be coated when said article iscoated.

BACKGROUND OF THE INVENTION

Prior to coating, a masking member is attached to a specific part (partto be masked) of an article to be coated. Said masking member may beremoved from said part after coating, drying and curing, by heating it,to dissipate the fluidity of its coating film. Accordingly, said maskingmember should have resistance to the heat treatment in the abovementioned coating process. Hitherto, a masking member, made of athermoplastic resin, in which an inorganic filler is mixed, has beenprovided as the masking member, having resistance to said heat treatment(see Patent Literature 1, for example).

In said thermoplastic resin, polypropylene has a particularly goodresistance to chemicals and solvents, and in a case where an inorganicfiller is mixed in with said polypropylene, the mechanical strength ofsaid polypropylene is reinforced and the heat resistance improves sincethe heat transfer coefficient of the polypropylene in which theinorganic filler is mixed rises, so that said masking member made ofpolypropylene in which an inorganic filler is mixed can be usedrepeatedly in the coating process.

Patent Literature; Tokkai Hei 2-126966

Generally, said masking member is manufactured by vacuum and/or pressureforming a polypropylene sheet in which an inorganic filler is mixed.Said polypropylene sheet, however, shows poor elongation, and it isdifficult to mold a molded article having a complex shape by vacuumand/or pressure forming. Nevertheless, in a case where saidpolypropylene sheet is sufficiently heated to be softened so as to makeit possible to mold easily a complex shape, said softened polypropylenesheet may be apt to droop under its own weight, making highly accuratemolding difficult.

DISCLOSURE OF THE INVENTION

Accordingly, to solve said problem, the present invention provides amasking member made of a modified polypropylene, in which 5 to 30% byweight of polyethylene and/or ethylene-propylene copolymer, is mixed inwith polypropylene. It is desirable that 20 to 50% by weight of aninorganic filler also be mixed in with said modified polypropylene.Further, said masking member is preferably manufactured by vacuum and/orpressure forming said modified polypropylene sheet.

Additionally, it is desirable that a non-modified polypropylene filmcover on one or both sides of said modified polypropylene sheet.

(Action)

Since polyethylene and/or ethylene-propylene copolymer is mixed in withsaid modified polypropylene as the material of the masking member of thepresent invention, said modified polypropylene sheet is heated at atemperature up to the point at which said modified polypropylene sheetdoes not droop under its own weight, and can be molded easily into ahighly accurate masking member, having a complex shape.

Nevertheless, in a case where the amount of polyethylene and/or ethylenepropylene copolymer mixed in is less than 5% by weight, the moldabilityof said polypropylene is insufficiently improved, masking it difficultto mold a complex shape, and in a case where the amount of polyethyleneand/or ethylene-propylene copolymer mixed in is beyond 30% by weight,said modified polypropylene has a poor hardness, meaning that its shapeand dimensional stability, and heat resistance may degrade.

By adding an inorganic filler to said modified polypropylene, itsmechanical strength improves and heat transfer coefficient rises,improving its heat resistance. Nevertheless, in a case where the amountof an inorganic filler mixed in is less than 20% by weight, animprovement in heat resistance is not remarkable, and in a case wherethe amount of an inorganic filler mixed in is beyond 50% by weight, saidmodified polypropylene sheet has poor elongation, resulting in poormoldability, and furthermore poor chemical resistance.

Generally, said modified polypropylene is molded into a sheet, and inthis case, said modified polypropylene sheet can easily be molded into acomplex shape, and vacuum and/or pressure forming which is(are) suitablyapplied to mass production can be employed.

In this case, when a non-modified polypropylene film cover one or bothsides of said modified polypropylene sheet, even in a case an inorganicfiller is mixed in with said modified polypropylene sheet, the surfaceof said sheet may be smoothed, and its chemical resistance is improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 to 4 relate to the first embodiment of the present invention.

FIG. 1 is a perspective view of a masking member, and the pillar towhich said masking member is attached.

FIG. 2 is a sectional view along the A-A line in FIG. 4, illustratingthe provisional attaching of said masking member to said pillar.

FIG. 3 is a sectional view along the A-A line in FIG. 4, illustratingthe final attaching of said masking member to said pillar.

FIG. 4 is a perspective view, illustrating a case where said maskingmember is attached to said pillar.

FIG. 5 relates to the second embodiment, and is a perspective view ofthe masking member and pillar to which said masking member is attached.

FIGS. 6 to 8 relate to the third embodiment.

FIG. 6 is a perspective view of a masking member, and the front bumperof the car to which said masking member is attached.

FIG. 7 is a side-sectional view, illustrating a case where said maskingmember is attached to said bumper.

FIG. 8 is a cross-sectional view, illustrating a case where said maskingmember is attached to said bumper.

FIGS. 9 to 12 relate to the fourth embodiment of the present invention.

FIG. 9 is a perspective view of a masking member, and the door windowframe of the car to which said masking member is attached.

FIG. 10 is a perspective view, illustrating a case where said maskingmember is attached to said window frame.

FIG. 11 is a sectional view along the A-A line in FIG. 10.

FIG. 12 is a sectional view along the B-B line in FIG. 10.

FIGS. 13 to 17 relate to the fifth embodiment of the present invention.

FIG. 13 is a perspective view of the masking member, and the instrumentpanel of a car before coating.

FIG. 14 is a sectional view along the A-A line in FIG. 13.

FIG. 15 is a perspective view, illustrating said instrument panel towhich said masking member is attached, after coating.

FIG. 16 is a sectional view along the B-B line in FIG. 15.

FIG. 17 is a perspective view of said instrument panel coated in twocolors.

FIG. 18 is a perspective view of the masking member of the seventhembodiment.

FIG. 19 is a perspective view of the masking member of the eighthembodiment.

DESCRIPTION OF NOTATIONS

11,21,31,41,51,61,71 masking member

DETAILED DESCRIPTION AND PREFERRED EMBODIMENT OF THE INVENTION

The present invention is precisely described below.

The material used for said masking member of the present invention is amodified polypropylene (hereafter to be described as modified PP) inwhich polypropylene (hereafter to be described as PP) is modified bypolyethylene (hereafter to be described as PE) and/or ethylene-propylenecopolymer (hereafter to be described as EPR). As said PE, any kinds ofPE such as a high density PE having a density higher than 0.941, anintermediate density PE having a density of between 0.926 and 0.940, alow density PE having a density of between 0.910 and 0.925, and ultralow density PE having a density lower than 0.909, can be used in thepresent invention, and a preferable PE is low density PE, having goodcompatibility with said PP and substantially improving elongation.

As said EPR, both rubbery copolymer of ethylene and propylene (hereafterto be described as EPM) and ethylene-propylene-diene terpolymer(hereafter to be described as EPDM), wherein ethylene, propylene, and adien component, such as dicyclopentadiene, ethylidene norbornene,1,4-hexadiene, or the like are terpolymerized, can be used.

Five to 30% by weight of PE and/or EPR is(are) mixed in with said PP. Ina case where PE and/or EPR is(are) mixed in with said PP in an amount ofbelow 5% by weight, the elongation of said PP is insufficientlyimproved, and good moldability can not be guaranteed. Further, in a casewhere PE and/or EPR is(are) mixed in with said PP in an amount of beyond30% by weight, the resulting modified PP has a poor hardness, poor shapeand dimensional stability, and poor heat resistance.

In said modified PP, one or more kind(s) of inorganic filler may beadded, said inorganic filler being such as calcium carbonate, magnesiumcarbonate, barium sulphate, calcium sulphate, calcium sulfite, calciumphosphate, calcium hydroxide, aluminum hydroxide, magnesium hydroxide,magnesium oxide, titanium oxide, iron oxide, zinc oxide, alumina,silica, diaton earth, dolomite, gypsum, talc, clay, asbestos, mica,calcium silicate, bentonite, white carbon, carbon black, iron powder,aluminum powder, glass powder, stone powder, blast furnace slag, flyash, cement, zirconia powder or the like. Generally, said inorganicfiller may be added to said modified PP in an amount of between 20 and50% by weight. In a case where said inorganic filler is added in anamount of below 20% by weight, the improvements in mechanical strengthand heat resistance are less evident, and in a case where said inorganicfiller is added in an amount of beyond 50% by weight, the moldabilityand chemical resistance of said modified PP sheet may degrade.

Further, one or more kind(s) of organic filler, such as linter, linen,sisal, wood flour, coconut flour, walnut flour, starch, wheat flour orthe like, natural fiber such as cotton, hemp, bamboo fiber, coconutfiber, wool, asbestos, kenaf, or the like; synthetic fiber such aspolyamide fiber, polyester fiber, polyolefin fiber, acrylic fiber, vinylchloride fiber, vinylidene choloride fiber or the like; semi syntheticfiber such as viscose fiber, acetate fiber, or the like, inorganic fibersuch as asbestos fiber, glass fiber, carbon fiber, ceramic fiber,metallic fiber, whisker, or the like may be added to said modified PP,to improve its shape and dimensional stability, and compression andtensile strength. Generally said filler(s) is(are) added to saidmodified PP in an amount of between about 0.05 and 200% by weight.

If necessary, one or more kind(s) of thermoplastic resin(s), such as avinyl chloride group resin, acrylic resin, methacrylic resin, vinylidenechloride group resin, vinyl propionate group resin, polyester groupresin, or the like may be mixed in with said modified PP.

Said modified PP may be colored by a pigment or dyestuff to distinguishits masking parts, and additionally, a plasticizer such as a DOP, DBP,or the like, an antioxidant, antistatic agent, crystallization agent,flame retardant, antiflaming agent, insecticide, antiseptic, variouswaxes, a lubricant, age resister, ultraviolet absorber, and a blowingagent of a chemical or capsule type, or the like may be mixed in withsaid polymer alloy. Two or more kinds of said agents may be mixed, andthen added to said modified PP.

To manufacture said masking member using said modified PP, a methodwherein said modified PP is molded by vacuum and/or pressure forming tobe a molded film or sheet, having a prescribed shape, is the mostsuitable method for molding a deep drawing shape or complex shape, andfor mass production, but, aside from said method, pressure forming,press molding, the blow forming, and injection molding also may beapplied in the present invention.

A film or expanded film of thermoplastic resin, such as polyolefin suchas PE, non-modified PP, EPR, ethylene-vinyl acetate copolymer, or thelike, polyvinyl chloride group resin, acrylic resin, methacrylic resin,poly-vinylidene chloride group resin, styren group resin, vinylpropionate group resin, styrene-butadiene copolymer, polyester groupresin, or the like, may be laminated onto said modified PP sheet on oneside or both sides.

In view of interlaminar adhesion and heat resistance properties, anon-modified PP film is preferable. When a filler, particularly aninorganic filler, is added to, and mixed with modified PP, said filmsecures the sheet surface's smoothness, improving its chemicalresistance. Usually a modified PP sheet's thickness is 300 to 600 μm,and when a film is formed on the surface of a sheet, the thickness ofsaid film is 10˜100 μm.

In order to enhance the affinity of the polymer alloy masking membersurface with paint or adhesive, a surface treatment such as a coronadischarge treatment, primer coating treatment, or the like, may beperformed.

The primer used for the primer coating treatment is, for example, asynthetic resin type primer, such as modified polyolefin, or an olefincopolymer (e.g. chlorinated polypropylene, ethylene-vinylacetatecopolymer), a synthetic rubber, such as styrene-butadiene rubber,acrylonitrile-butadiene rubber, chloroprene-rubber, polybutadien, or thelike; an acrylic synthetic resin, vinyl synthetic resin, an acrylicsynthetic resin containing an amino group and/or amide group, a vinylsynthetic resin containing an amino group and/or amide group, an aminosynthetic resin, epoxy resin or the like; and a low-molecular weightcompound primer, such as aluminum alcholate or an aluminum chelateagent, such as aluminum isopropylate, aluminum triacetylacetonate, orthe like; an alkyl metal, such as 2-ethylhexyl lead, hexadecyl lithiumor the like; an organotin compound, such as dibutyl tin diacetate,di-n-butyl tin dioxide, or the like; a silane compound, such asmethylvinyl dichloro silane, or the like; a metal complex salt of a 1,3-dicarbonyl compound, such as acetylacetone lithium, acetylacetoneberyllium, or the like; an organotitanium compound, such as tetrabutyltitanate, or the like; a boric acid compound, such as tri-n-butylborate, triphenyl borate, or the like; a phosphate, such as trioleilphosphate, tridecyl phosphate, or the like; a metal salt of carboxylicacid, such as magnesium stearate, cobalt naphtenic acid, or the like; ametal thioalcholate, such as n-potassium dodecylmercapto chloride, orthe like; a thiodicarboxylate, such as zinc 2-ethylhexanedithiocarboxylate, or the like; a metal salt of dithiocarbamic acid,such as nickel dimethyldithiocarbamate, copper dimethyldithiocarbamateor the like; a metal salt of sulfonic acid, such as nickelbenzenesulfonate, or the like; an organophosphate compound such asdibutylvanadium phosphate, or the like. One or more kinds of said primermay be used together.

A preferable primer is an acrylic synthetic resin, containing aquarternary ammonium salt, or an amino group synthetic resin.

For the primer coating treatment, a solution or emulsion(latex) of oneor more kinds of said primer is coated on the surface of saidengineering plastic as the material for the masking member, and thendried.

Prior to said primer coating treatment, an affinity treatment may beexercised on the surface of said engineering plastic. Examples of saidaffinity treatment include flame treatment, sulfuric acid treatment,corona discharge treatment, or the like, with the surface of saidengineering plastic being slightly carbonized by said treatment, to gainaffinity with the other synthetic resin.

Embodiments The First Embodiment

FIGS. 1 to 4 relate to the first embodiment of the present invention.The masking member (11) of this embodiment is used to protect pillarshaped members, such as the center pillar (12) of a car from beingcoated. Said masking member (11) consists of a body (11A) having aU-shape in cross section, to the inside (11B) of which the body (12A) ofthe center pillar (12) is to be fitted, a pair of flange grooves (11D,11D) formed along the lower edges of the side walls (11C, 11C) of saidbody (11A) into which the pair of flanges (12B, 12B) from said centerpillar (12) are each to be inserted, a pair of back side applicationparts (11E, 11E) each extending from said flange grooves (11D, 11D), andan upper side application part (11F) extending from the top of said body(11A), with a reinforcing longitudinal rib (11G) and reinforcinghorizontal ribs (1H) being formed around the circumference of said body(11A).

Said masking member (11) is manufactured by vacuum forming a modified PPsheet (the thickness 340 μm), wherein 18% by weight of low density PE ismixed in with PP, with 30% by weight of talc being mixed with saidmodified PP.

As shown in FIG. 2, said masking member (11) is provisionally attachedto the body (12A) of said center pillar (12) by fitting said body (12A)to the inside (11B) of said body (11A) of said masking member (11), andthen further inserting each flange (12B, 12B) of said center pillar (12)into the flange grooves (11D, 11D) of said masking member (11).

After said provisional attachment, said back side application parts(11E, 11E) are each applied to the back side panel (12C) of said centerpillar (12), turning said back side application parts (11E, 11E) to therear, and said back side application parts (11E, 11E) being fixed tosaid back side panel (12C) with adhesive tape (14), tacks, or the like,as shown in FIG. 3.

After said masking member (11) is attached to said center pillar (12),as shown in FIG. 4, the car is coated with a thermosettingmelanine-alkyd resin paint or the like.

The Second Embodiment

FIG. 5 relates to the second embodiment of the present invention. Themasking member (21) of this embodiment consists of a body (21A) having aU-shape in cross section, to the inside (21B) of which the body (22A) ofa center pillar (22) is to be fitted, a pair of flange grooves (21D,21D) formed along the lower edges of the side walls (21C, 21C) of saidbody (21A), into which a pair of flanges (22B, 22B) from said centerpillar (22) are each to be inserted, a pair of back side applicationparts (21E, 21E) extending from said flange grooves (21D, 21D), and anupper side application part (21F) extending from the top of said body(21A), with a plural number of reinforcing longitudinal ribs (21G) andreinforcing horizontal ribs (21H) being formed around the circumferenceof said body (21A).

Being different from the first embodiment, said reinforcing longitudinalribs (21G) are formed intermittently in this embodiment.

Said masking member (21) is manufactured by vacuum-pressure forming alaminated sheet wherein a non-modified PP film (thickness 30 μm) islaminated onto both sides of a compound sheet (thickness 320 μm), saidcompound being made of a modified PP, in which 15% by weight of EPDM ismixed in with PP, with 35% by weight of calcium carbonate and 3% byweight of carbon black being mixed in with said modified PP.

In the same way as stated in the first embodiment, said masking member(21) is provisionally attached to the body (22A) of said center pillar(22) by fitting said body (22A) to the inside of said body (21A) of saidmasking member (21), and then further inserting each of said flanges(22B, 22B) from said center pillar (22) into the flange grooves (21D,21D) of said masking member (21), following which the back sideapplication parts (21E, 21E) are both applied to the back side panel ofsaid center pillar (22), turning said back side application parts (21E,21E) to the rear, said back side application parts (21E, 21E) beingfixed to said back side panel (22), with adhesive tape, tacks, or thelike.

After said masking member (21) is attached to said center pillar (22),the car is coated with paint.

In the first embodiment, said masking member (11) is apt to bendhorizontally along said reinforcing longitudinal rib (11G), since saidrib (11G) is continuous, while in this embodiment, said masking member(21) has increased horizontal bending strength along its ribs (21G),since said ribs (21G) are intermittent.

The Third Embodiment

FIGS. 6 to 8 relate to the third embodiment of the present invention. Asshown in FIG. 6, a car body (33) has a front bumper (34) and when saidcar body (33) is coated, the masking member (31) of this embodiment isattached to the air inlet hole (36) of the lower skirt part (35) of saidfront bumper (34). A plural number of reinforcing frame bars (36A, 36B)are equipped lengthwise and breadthwise, with a pair of support pillars(36C) being equipped on either side of said air inlet hole (36).Correspondingly, the frame bar grooves (32A, 32B), for the insertion ofsaid reinforcing frame bars (36A, 36B), are equipped lengthwise andbreadthwise in said masking member (31), with a pair of pillar grooves(32C) for the insertion of said support pillars (36C) being equipped oneither side of said masking member (31). A flange (32D) is formed alongthe front of said masking member (31), further, a pressure sensitiveadhesive layer (32E) is formed around the circumference of said maskingmember (31).

Said fitting grooves (32A,32B,32C), for the insertion of saidreinforcing frame bars (36A, 36B), and a pain of support pillars (36C),work as ribs to support said masking member (31). At the cross point ofthe horizontal (longitudinal) fitting groove (32B), and the vertical(short side direction) fitting groove (32A), said horizontal fittinggroove (32B) overlaps said vertical fitting groove (32A), for thepurpose of improving the horizontal rigidity of said masking member(31), while at the cross point of said vertical fitting groove (32C),and horizontal (short side direction) fitting grove (32B), said verticalfitting groove (32C) overlaps said horizontal fitting groove (32B), toimprove the rigidity of said masking member (31) in its verticaldirection.

Said masking member (31) is manufactured by vacuum forming a laminatedsheet wherein a non-modified PP film (thickness 30 μm) is laminated ontoboth sides of a compound sheet (thickness 350 μm), said compound beingmade of made of a modified PP, in which 20% by weight of low density PEis mixed in with PP, with 20% by weight of talc, 5% by weight of calciumcarbonate, and a small amount of antistatic agent and antioxidant beingmixed in with said modified PP.

Said masking member (31) is fitted to the inside of said air inlet hole(36), with each reinforcing frame bar (36A, 36B) being inserted intoeach frame bar groove (32A, 32B), and each support pillar (36C) beinginserted into each pillar groove (32C), following which said maskingmember (31) is then fixed to the inside of said air inlet hole (36) byits pressure sensitive adhesive layer (32E). Said pressure sensitiveadhesive layer (32E) may not always be necessary in the presentinvention.

As described above, said masking member (31) is attached to said airinlet hole (36) of the skirt part (35), which is a masking part, afterwhich said car body (33) is coated with paint, following which, theresulting coating film is cured by heating.

The Fourth Embodiment

FIGS. 9 to 12 relate to the fourth embodiment of the present invention.The masking member (41) of this embodiment is used to protect the windowframe (44A) of a car door (44), and said masking member (41) consists ofthree parts (41A, 41B, 41C), each part in cross section being L-shaped.A longitudinal reinforcing rib (41D) and cross ribs (41E) are formed ineach part (41A, 41B, 41C).

Said masking member (41) is manufactured by vacuum-pressure forming alaminated sheet, wherein a non modified PP film (thickness 50 μm) islaminated onto a compound sheet, (thickness 350 μm), said compound beingmade of a modified PP, in which 30% by weight of low density PE is mixedin with PP, with 27% by weight of talc being mixed in with said modifiedPP, and the surface of said masking member (41) receives a coronadischarge treatment.

In order to attach said masking member (41) to said window frame (44A)of the door (44), each part (41A, 41B, 41C) is attached to said windowframe (44A), overlapping each of the connecting ends of said parts (41A,41B, 41C), said overlapping connecting ends being fixed with adhesivetape (42), etc. as shown in FIG. 10.

In this case, as for said overlapping connecting ends, a cross rib (41E)from the connecting end of one part (41A or 41B) is fitted under a crossrib (41E) from the connecting end of the other part (41B or 41C) asshown in FIG. 11, with an upper edge hook part (41F) from each part(41A, 41B, 41C) being hung on the upper edge of said window frame (44A)as shown in FIG. 12. After coating, said masking member (41) is removedfrom said window frame (44A) of the door (44). Said window frame (44A)is not coated with paint since said window frame (44A) was protected bysaid masking member (41).

Since the surface of said masking member (41) has received a coronadischarge treatment, the layered paint formed on the surface of saidmasking member (41) adhere firmly to the surface of said masking member(41), so that the scattering of pieces of dried paint peeling from thesurface of said masking member (41) is effectively avoided.

The Fifth Embodiment

FIGS. 13 to 17 relate to the fifth embodiment of the present invention.In the front of the instrument panel (52) an installation port (55) intowhich a globe component is installed, installation ports (56, 57) intowhich an audio system is installed, an installation port (58) into whichinstruments are installed, and an installation port (59) into which asmall articles box is installed, or the likes are provided, saidinstrument panel being divided into an upper section (52A) and a lowersection (52B).

As shown in FIG. 14, said instrument panel (52) consists of a base (54)and a surface trim (53) which is applied to the surface of said base(54), and said surface trim (53) consists of a surface layer (53A) madeof a non-woven fabric, synthetic leather, or the like, and a waddinglayer (53B) made of a non-woven fabric, foamed plastic sheet or thelike, backed with said surface layer (53A), and further said surfacelayer (53A) is colored with a designated color (base color), and thethickness of said wadding layer (53B) can be elastically compressible.

Along the boundary between said upper section (52A) and said lowersection (52B), a groove (54A) is formed in said base (54), with aparting line PL being formed by the insertion of said surface trim (53)into said groove (54A). Said surface trim (53) is fixed to said grooves(54A) with the thickness of said wadding layer (53B) having beencompressed, then rebounding elastically. Since said instrument panel(52) is decorated with said surface trim (53) common to both the upperand lower sections, both upper section (52A) and said lower section(52B) are the same color. Said instrument panel (52) may be installedinto the car body as it is, or in a case where said instrument panel's(52) upper and lower sections (52A,52B) are different colors, a maskingmember (51) is used as shown in FIG. 13. Said masking member (51) has ashape corresponding to that of said instrument panel's upper section(52), with an engaging flange (51A) being formed around thecircumference edge of said masking member (51).

As shown in FIG. 15, said masking member (51) is applied to saidinstrument panel's upper section (52A), and as shown in FIG. 16, isfixed by the insertion of said engaging flange (51A) into the slit S ofsaid parting line PL. By the insertion of said engaging flange (51A) ofsaid masking member (51) into said slit of said parting line PL, thethickness of said wadding material (51B) of said surface trim (53) iscompressed, so that said engaging flange (51A) is pinched and fixed tosaid surface trim (53), due to said wadding material's rebund andelasticity. As described above, said masking member (51) is applied tosaid instrument panel's upper section (52A), after which said instrumentpanel's lower part (52B) is coated in a different color from said upperpart (52A) by a method such as spray coating. After coating, saidmasking member (51) is removed from said upper part (52A).

In the above-described manner, said instrument panel (52), whose upperand lower sections are each coated in different colors, is easilyprepared, as shown in FIG. 17.

Said masking member (51) is manufactured by vacuum forming or pressmolding a laminated sheet wherein a non-modified PP film (thickness 20μm) is laminated onto the surface of a compound sheet (thickness 350μm), said compound being made of a modified PP, in which 10% by weightof intermediate density PE and 12% by weight of EPM are mixed in withPP, with 20% by weight of talc and 10% by weight of carbon black beingmixed in with said modified PP.

The Sixth Embodiment

A masking member having the same shape as said masking member of THEFIRST EMBODIMENT is manufactured by the same method as THE FIRSTEMBODIMENT by using a compound sheet (thickness 350 μm), said compoundmade of a modified PP in which 20% by weight of low density PE and 5% byweight of polystyrene are mixed in with PP, with 25% by weight ofcalcium carbonate being mixed in with said modified PP.

Said masking member of this EMBODIMENT is used to mask the centerpillar, the same as said masking member of THE FIRST EMBODIMENT.

The Seventh Embodiment

A masking member (61), as shown in FIG. 18 was manufactured, after whichit was used for the masking of the air inlet hole (36) of said frontbumper (34) of the car in THE THIRD EMBODIMENT.

In said masking member (61), there are fitting grooves (32A, 32B, 32C)into which said reinforcing frame bars (36A, 36B) and said supportpillars (36C, 36C) are each to be inserted, with convex parts (62, 62)projecting from the front of said masking member (61), and a flange(32D) being formed around the front of said masking member (61). Thelengthwise rigidity of said masking member (61) is improved by theconvex shape of said parts (62, 62). By improving its lengthwiserigidity, the swelling at either end of said masking member (61) beingcaused by warping of said masking member (61) is prevented, said warpingbeing caused by the curing of the paint film applied to said maskingmember during coating.

Although said reinforcing frame bars (36A, 36B) do not fit into saidconvex parts (62, 62), said masking member (61) is fixed to said airinlet hole (36) with said fitting grooves (32A, 32B, 32C), without anytrouble.

Generally, in a masking member of this type (61), it is not alwaysnecessary to set all of said fitting grooves (32A, 32B, 32C) into whichall of said reinforcing frame bars (36A, 36B) and, said support pillars(36C, 36C) are to be inserted, as long as the necessary number offitting grooves (32A, 32B, 32C) to fix said masking member (61) to saidair inlet hole (36) are provided. Further, concave parts may be formedinstead of said convex parts (62, 62), and are expected to have the sameeffect.

Said masking member (61) of this EMBODIMENT was manufactured by the samemethod as described in THE THIRD EMBODIMENT using a laminated sheetwherein a non-modified PP film (thickness 30 μm) is laminated onto bothsides of a modified PP sheet (thickness 320 μm), in which 15% by weightof low density PE and 5% by weight of polystyrene-ethylacrylatecopolymer is mixed in with PP.

The Eighth Embodiment

The masking member (71), shown in FIG. 19, for the masking of the airinlet hole (36) of said front bumper (34) of the car in THE THIRDEMBODIMENT was manufactured.

In said masking member (71), there are fitting grooves (23A, 32B, 32C)into which said reinforcing frame bars (36A, 36B), and said supportpillars (36C,36C) are fitted, vertical ribs (72, 72), horizontal ribs(73, 73), and a flange (32D) being formed along the front of saidmasking member (71). Although said fitting grooves (32A, 32B, 32C) workas ribs, the rigidity of said masking member (71) in both its verticaland horizontal directions is further improved by said vertical ribs (72,72) and horizontal ribs (73, 73).

These ribs give rigidity to the masking member in its lengthwisedirection, but degrade its rigidity in its crosswise direction, sincethe masking member is apt to be folded at said rib. However, at thecross point of ribs, in a case where one rib overlaps another, therigidity along said overlapping rib can be improved.

As for the masking member (71) of this embodiment, since said horizontalribs (73,73) are settled to overlap said vertical ribs (72,72), thelengthwise (horizontal) rigidity of said masking member (71) is greatlyimproved. By improving the lengthwise rigidity of said masking member(71), the swelling at either end of said masking member (71) caused bywarping of said masking member (71) is prevented, said warping beingcaused by the curing of the paint coating film applied to said maskingmember (71), during coating.

Said masking member (71) of this EMBODIMENT was manufactured by the samemethod as described in THE THIRD EMBODIMENT, using a laminated sheet,wherein an EPM film (thickness 27 μm) is laminated on to a modified PPsheet (thickness 340 μm), in which 20% by weight of low density PE, and10% by weight of high density PE are mixed in with PP.

INDUSTRIAL UTILITY

Said modified PP, used as the material of the masking member of thepresent invention, has excellent resistance to heat, chemicals andsolvents, and excellent moldability, and by using said modified PP, amasking member having deep drawing shape or complex shape is certainlymanufactured, said modified PP having especially excellent moldabilityfor vacuum forming, vacuum-pressure forming, and pressure forming,which, are suitable methods for mass-production, the resulting maskingmember can be molded into any shape corresponding to the shape of thepart to be masked.

1. A masking member made of a modified polypropylene sheet in which 5 to30% by weight of polyethylene and/or ethylene-propylene copolymer ismixed in with polypropylene, said masking member being manufactured byvacuum and/or pressure forming said modified polypropylene into aprescribed shape.
 2. A masking member in accordance with claim 1,wherein 20 to 50% by weight of an inorganic filler is mixed in with saidmodified polypropylene.
 3. (canceled)
 4. A masking member in accordancewith claim 1, wherein a non-modified polypropylene film covers one orboth sides of said modified polypropylene sheet.
 5. A masking member inaccordance with claim 2, wherein a non-modified polypropylene filmcovers one or both sides of said modified polypropylene sheet.